Attention this is a small model, there is no more pockets.
The internal compartments are removable,
and there is a small removable bag to put his phone or something else attached to the shoulder strap.
It is sold with exorbitant prices on the specialized sites in the photo or major retailers (3 times the Amazon price) so it's roughly the same price discounters in the net.
To switch the bag in "sling" to easily grab his camera,
you just let the whole shoulder
then turn the bag into the belly swinging above the shoulder.